Investigations of Palladium Catalysts on Different Carbon Supports

Albers, Peter; Burmeister, R.; Seibold, K.; Prescher, G.; Parker, Stewart F.; Ross, D.K.

doi:10.1006/jcat.1998.2279

Cited by 74 publications

(65 citation statements)

References 33 publications

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“…These results are in line with the study made by Jackson et al for propyne hydrogenation 43 which reported that the "acidic" catalyst retained 3 times less carbon on its surface after 1 pulse of propyne and 16 times less after reaching a steady state. Similarly, it was shown for Pd particles deposited on differently treated activated carbons by the inelastic neutron scattering technique 30 that the higher the carbon acidity, the less carbonaceous deposits are formed. The herein observed effect of acidity on the catalyst selectivities can be rationalized considering a change in the adsorption strength of acetylene/ethylene (see paragraph 3.4.1).…”

Section: Initial Selectiwity To Ethylene and To Byproductmentioning

confidence: 99%

Monodispersed Pd Nanoparticles for Acetylene Selective Hydrogenation: Particle Size and Support Effects

2008

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Monodispersed Pd nanoparticles (8, 11, and 13 nm in diameter) as confirmed by high resolution transmission electron microscopy were prepared via the reverse microemulsion method and deposited on structured supports consisting of carbon nanofibers (CNF) grown on sintered metal fibers (SMF). The CNF/SMF supports were subjected to oxidative treatments to introduce O-functional groups on the CNF surface. These groups were characterized by temperature-programmed decomposition (TPD) and X-ray photoelectron spectroscopy. The catalysts were used to study (a) the effect of Pd size and (b) the effect of the support nature on the selective acetylene hydrogenation. Antipathetic size dependence of TOF disappeared at particle size bigger than 11 nm. Initial selectivity to ethylene was found size-independent. The deactivation due to coke deposition was faster for smaller particles. The structure-sensitivity relations for the catalysts investigated are discussed in terms of "geometric" and "electronic nature" of the size effect and rationalized regarding Pd-C x phase formation which is size-dependent. Supports with increased acidity diminished the formation of coke and changed the byproduct distribution toward ethane.

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Section: Initial Selectiwity To Ethylene and To Byproductmentioning

confidence: 99%

Monodispersed Pd Nanoparticles for Acetylene Selective Hydrogenation: Particle Size and Support Effects

2008

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“…In recent years, carbon materials such as carbon nanotubes (CNTs), carbon nanofibers and mechanically milled graphites have attracted attention owing to the availability of new carbon materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. However, most studies concerning the hydrogen storage have been carried out at high pressures (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) and low temperatures (80-133 K) in order to store molecular hydrogen by physisorption. It has been often reported that hydrogen storage by physisorption remains less than 4 wt% at room temperature and even high pressures [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…Our methodology here of the hydrogen storage is to adsorb atomic hydrogen at the defect sites of CNTs after dissociation of H 2 by Pd catalyst particles attached to the CNTs [15][16][17]. La catalysts have been doped to CNTs in order to introduce the defect sites [17], which catalyze oxidation of CNTs by O 2 .…”

Section: Introductionmentioning

confidence: 99%

Possibilities of atomic hydrogen storage by carbon nanotubes or graphite materials

Yoo

Habe

Nakamura³

2005

Science and Technology of Advanced Materials

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Atomic hydrogen storage by carbon nanotubes (CNTs) and highly oriented pyrolytic graphite (HOPG) has been studied using a flow catalytic reactor and an ultra-high vacuum surface science apparatus including scanning tunneling microscope (STM), respectively. Defect sites on CNTs as adsorption sites of atomic hydrogen are introduced by oxidation pretreatment using La catalyst. Pd catalysts are then deposited on CNT surfaces for dissociation of H 2 into atomic hydrogen, which spills over to the defect sites. In the best case, 1.5 wt% of hydrogen is stored in the defective CNT with Pd particles at 1 atm and 573 K. In temperature programmed desorption (TPD) experiments, H 2 starts to desorb at 700-900 K depending on the annealing temperatures of CNTs prior to hydrogen storage. On the HOPG surface, hot atomic hydrogen produced by dissociation of H 2 using tungsten wire desorbs from graphite terraces at 400-700 K, which is much lower than that on CNTs. It is possible that one can decrease the desorption temperature by changing the method of H 2 dissociation. q

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“…Catalysts prepared from incipient wetness are usually known to have small particle size throughout the whole support surface due to quick adsorption of precursors by capillary force. 8 Therefore, it is expected that an eggshell-type metal distribution was formed on Pd/C (PD) and a uniform metal distribution was formed on Pd/C (IW). The metal distribution in Pd/C (Kawaken) seems to be in the intermediate range.…”

Section: Resultsmentioning

confidence: 99%

Effect of Catalyst Preparation on the Selective Hydrogenation of Biphenol over Pd/C Catalysts

Cho

Park²,

Hong³

et al. 2008

Bulletin of the Korean Chemical Society

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The effects of catalyst preparation on the reaction route and the mechanism of biphenol (BP) hydrogenation, which consists of a long series-reaction, were studied. Pd/C catalysts were prepared by incipient wetness method and precipitation and deposition method. The reaction behaviors of the prepared catalysts and a commercial catalyst along with the final product distributions were very different. The choice of the catalyst preparation conditions during precipitation and deposition including the temperature, pH, precursor addition rate, and reducing agent also had significant effects. The reaction behaviors of the catalysts were interpreted in terms of catalyst particle size, metal distribution, and support acidities.

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Investigations of Palladium Catalysts on Different Carbon Supports

Cited by 74 publications

References 33 publications

Monodispersed Pd Nanoparticles for Acetylene Selective Hydrogenation: Particle Size and Support Effects

Monodispersed Pd Nanoparticles for Acetylene Selective Hydrogenation: Particle Size and Support Effects

Possibilities of atomic hydrogen storage by carbon nanotubes or graphite materials

Effect of Catalyst Preparation on the Selective Hydrogenation of Biphenol over Pd/C Catalysts

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